This invention relates to improvements to blade shields for shaving. For as long as man has attempted the removal of hair from the body, energies have been directed to ameliorating the effects of the sharpened cutting edge on the skin of the user. Despite all efforts, occasional skin irritation and bloodletting still occur during the shaving process.
This invention relates to particular, but not exclusively so, to the deposition preferably under vacuum conditions, of structural elements on the body of the blade and more particularly to the providing of a guard over the blade edge so as to protect the user from nicking or cutting of the skin.
Hitherto numerous methods have been devised to minimize this aspect of shaving, a large portion directed to improved forms of edge guard. A patent to Dickinson, U.S. Pat. No. 1,035,548, issued Aug. 13, 1912, discloses a straight razor having a long blade on which is spirally wound a wire or thread to form a guard. Another form of guard is disclosed by Ferraro in U.S. Pat. No. 3,263,330 issued Aug. 2, 1966, wherein the razor blade cutting edge is encapsulated in a folded sheet of metal having a row of holes through which the hairs but not the skin pass for cutting.
A more recent development is disclosed in U.S. Pat. No. 3,505,734 issued to Iten on Apr. 14, 1970, for a cutting blade with self-contained guard. In this patent a razor blade with a self-contained guard in the form of a wire is described. The wire or thread of selected diameter is wound about the body of the blade encompassing its ultimate edge. The spacing or pitch between successive turns of the wire is controlled relative to its diameter to provide protection to the skin of the user and diminished probability of cutting or nicking. With the selected critical thread diameter and spacing between successive thread portions at the cutting edge the blade may be drawn across the skin without coming in contact therewith.
While the self-contained guard of Iten has proven relatively successful in insulating the skin from the ultimate cutting edge of the razor blade, it does introduce numerous and severe problems into the manufacturing of razor blades incorporating its principal features. The thread must be of flexible material having precise dimensional conformity. It must also be sufficiently flexible for winding about the body of the blade and yet strong enough to withstand severing as it passes over and comes in contact with the blade edge. Moreover, once the wire is placed on the blade it must be adhesively or otherwise locked into position to prevent interference with shaving and to maintain its advantageous characteristics. With regard to this latter fact, it must be kept in mind that as the wire comes into contact with the ultimate edge of the blade, the edge being 300 to 500 Angstroms in radius, it necessarily seriously damages the blade edge making such contact portion substantially incapable of providing comfortable shaving characteristics. Such winding process also inherently increases blade damage resulting in a less efficient manufacturing operation.
It is an object of the preferred form of the invention to provide an improved method for applying structural elements to a cutting or razor blade. It is another object of the present invention to provide a razor blade product having structural elements thereon. Another object of the present invention is to provide a razor blade having a vacuum deposited guard formed thereon. Yet another object of the present invention is to provide for the placement of a guard over the ultimate edge of a razor blade in a more efficient and economical manner.